A Non-Contact Technique for Damage Monitoring in Submerged Plates Using Guided Waves

This paper discusses a non-contact and in situ damage-monitoring methodology in submerged plates using ultrasonic guided waves. Specific Lamb wave modes sensitive to near-surface and sub-surface damages have been identified. These modes are further utilized for non-contact scanning of the plates to identify the presence, as well as extent, of damage. Effective combination of specific Lamb wave modes leads to comprehensive inspection of the submerged plate structures. The developed methodology is successfully applied for monitoring notches and corrosion in plate. The data generated from scanning the plates have been pictorially represented in the form of defect maps.